This invention relates to optical information storage disks. More particularly, to prevent access to counterfeit copies of such disks.
The software industry is at a crossroads at this time. More and more software is being delivered on compact disc (CD) for its cost effectiveness and ease of installation, ease of operation and the reduced cost of media and associated documentation. At the same time, the CD-Recordable industry is set to explode into the consumer market as prices for CD recorders are sharply decreasing. The cost of blank CD recordable media will also drop as more and more consumers purchase recorders and economy of scale manufacturing brings the cost down.
While taken individually these two trends are exciting and very beneficial for the consumer, together these two trends are troubling for the software publishing industry. CD recordable (CD-R) technology allows very cost effective duplication of CD products, referred to in the software industry as CD-ROM. Piracy is the predominant concern of all those who publish intellectually valuable content on CD-ROM, since it is now easily copyable onto a CD-R disc. The need therefore exists to make a CD-ROM uncopyable to thwart illegal piracy of its content.
The basic premise that is fundamental to the present invention is that the information recorded on CD-ROM and other CD media or optical media is laid out in a continuous spiral track. This track is usually (but not necessarily) read in a Constant Linear Velocity mode.
The mechanisms which read the data contained in these types of discs rely on the spiral track for not only for data, but also for tracking and location information as well. Mechanisms are built into the data recording standard which allow for defects in the media itself (defects from manufacturing as well as from misuse and damage/scratches) to be corrected. The mechanism to correct for defects is suited to defects which are characterized by certain physical and electrical limits. If these limits are exceeded, then the mechanism to correct errant data does not work. The result is an unreadable disc within the flaw causing a disruption. The disruption is enough to cause an error in the reader. This error is returned as unrecoverable and the read operation is disrupted. This disruption halts all attempts to copy data in the area within the defect.
This behavior works for copy protection because any attempt to image copy the optical media results in failure. The applications contained within an authorized copy of the optical disc can be made to work normally by making them aware of the flawed area on the disc. Since computer addressable readers like CD-ROM drives can jump discretely to any area of the disc, under software control, the flaw can be bypassed, allowing 100% functionality.
Therefore, by introducing defects selectively onto optical media such as CD-ROM, and making the applications contained within the media aware of the defects, a very effective copy protection process which is highly resistive to reverse engineering is created.
The present invention is a method and apparatus for making optical discs copy protected. The method requires that the software contained in the optical media be aware of defect in the optical media created by the method. By introducing special areas herein called the xe2x80x9cMARKxe2x80x9d on the media, and making the software contained within the media aware of the MARK, it is possible to thwart unauthorized copying of the optical media. The method is effective since the MARK is placed on the media via special manufacturing techniques hereinafter referred to as the xe2x80x9cPROCESS.xe2x80x9d The PROCESS requires specialized equipment whose operations are difficult if not impossible, t:o reproduce using a conventional off-the-shelf desktop CD-Recorder. The software delivered in the media can be of any type, i.e. data or application. Access to the content of the media is established via executable code contained on the media which seeks and accesses the MARK. The software which is aware of the MARK is referred to herein as the xe2x80x9cCODExe2x80x9d.